18650 Lithium Battery was named as per IEC naming guidelines, but dimensions of 18650 Lithium Battery made by different manufacturers are not the same.
According to IEC 1960 standard, secondary battery is marked as follow:
1). Battery mark consists of three letters+ five numbers (cylindrical) or +six numbers (square).
2). First letter indicates battery cathode material. Letter “I” refers to built-in lithium ions; letter “L” means lithium metal electrode or lithium alloy electrode.
3). Second letter represents battery’s anode material. C: Co-based electrode; N: Ni-based electrode; M: Mn-based electrode; V: vanadium-based electrode. At present, besides previous lithium manganese oxide material,, 18650 anode material system has added other materials, like LiFePo4, LiMnO, tri-materials. However, 18650 lithium battery dimension remains the same.
4). Third letter: refers to battery shape. R-cylindrical battery; L-prismatic battery.
5). Numbers: five letters separately indicates cylindrical battery’s diameter and height. Diameter unit is mm and height unit is one tenth mm. In case diameter or height exceeds or equals 100mm, a slant line should be added between two dimensions.
The aforesaid battery is commonly known as lithium battery cell in the industry. ICR18650 indicates a cylindrical rechargeable lithium-ion battery with Co as anode material, diameter of 18mm and height of 65mm.
Due to different manufacturer’s technology, dimension of 18650 lithium cell is just an approximate number. That is, reasonable error value is allowed. According to international customs, design dimension of 18650 cell should be diameter: 18±0.2mm and height: 65mm.
